a(n) = Sum_{k=0..n} binomial(n+k-1,k) * binomial(n+k-1,n-k).
A378565
a(n) = Sum_{k=0..n} binomial(n+k-1,k) * binomial(n+k-1,n-k).
Terms
- a(0) =1a(1) =1a(2) =7a(3) =43a(4) =271a(5) =1746a(6) =11425a(7) =75615a(8) =504799a(9) =3392953a(10) =22930282a(11) =155664356a(12) =1060710457a(13) =7250779238a(14) =49700101101a(15) =341474150583
External references
- oeis: A378565